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Question:

A tent is in the shape of a cylinder surmounted by a conical top. If the height and diameter of the cylindrical part are 2.1m and 4m respectively, and the slant height of the top is 2.8m, find the area of the canvas used for making the tent. Also, find the cost of the canvas of the tent at the rate of Rs 500 per m². (Note that the base of the tent will not be covered with canvas.) (Use π=22/7).

Solution:

Given:
Height (h) of the cylindrical part = 2.1m
Diameter of the cylindrical part = 4m
Radius of the cylindrical part = 2m
Slant height (l) of conical part = 2.8m
Area of canvas used = CSA of conical part + CSA of cylindrical part
= πrl + 2πrh
= π × 2 × 2.8 + 2π × 2 × 2.1
= 2π[2.8 + 4.2]
= 2 × 22/7 × 7
= 44m²
Cost of 1m² canvas = 500 rupees
Cost of 44m² canvas = 44 × 500 = 22000 rupees.
Therefore, it will cost 22000 rupees for making such a tent.